Using flat regmap cache instead of RB-tree to avoid the following
lockdep warning on driver load:
[ 0.697285] WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:2755
lockdep_trace_alloc+0x15c/0x160()
[ 0.697449] DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))
The RB-tree regmap cache needs to allocate new space on first
writes. However, allocations in an atomic context (e.g. when a
spinlock is held) are not allowed. The function regmap_write
calls map->lock, which acquires a spinlock in the fast_io case.
Since the FSL DCU driver uses MMIO, the regmap bus of type
regmap_mmio is being used which has fast_io set to true.
The MMIO space of the DCU driver is reasonable condense, hence
using the much faster flat regmap cache is anyway the better
choice.
Signed-off-by: Stefan Agner <stefan at agner.ch>
Cc: Mark Brown <broonie at kernel.org>
---
Changes since v1:
- Do not move drm_dev_alloc
drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c | 18 +++++++++++-------
drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h | 6 ++++--
2 files changed, 15 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
index e01c813..9c21aad 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
@@ -36,11 +36,11 @@ static bool fsl_dcu_drm_is_volatile_reg(struct device *dev,
unsigned int reg)
return false;
}
-static const struct regmap_config fsl_dcu_regmap_config = {
+static struct regmap_config fsl_dcu_regmap_config = {
.reg_bits = 32,
.reg_stride = 4,
.val_bits = 32,
- .cache_type = REGCACHE_RBTREE,
+ .cache_type = REGCACHE_FLAT,
.volatile_reg = fsl_dcu_drm_is_volatile_reg,
};
@@ -260,12 +260,14 @@ static const struct fsl_dcu_soc_data fsl_dcu_ls1021a_data
= {
.name = "ls1021a",
.total_layer = 16,
.max_layer = 4,
+ .max_register = LS1021A_DCU_MAX_REGISTER,
};
static const struct fsl_dcu_soc_data fsl_dcu_vf610_data = {
.name = "vf610",
.total_layer = 64,
.max_layer = 6,
+ .max_register = VF610_DCU_MAX_REGISTER,
};
static const struct of_device_id fsl_dcu_of_match[] = {
@@ -331,6 +333,13 @@ static int fsl_dcu_drm_probe(struct platform_device *pdev)
return ret;
}
+ id = of_match_node(fsl_dcu_of_match, pdev->dev.of_node);
+ if (!id)
+ return -ENODEV;
+
+ fsl_dev->soc = id->data;
+
+ fsl_dcu_regmap_config.max_register = fsl_dev->soc->max_register;
fsl_dev->regmap = devm_regmap_init_mmio(dev, base,
&fsl_dcu_regmap_config);
if (IS_ERR(fsl_dev->regmap)) {
@@ -338,11 +347,6 @@ static int fsl_dcu_drm_probe(struct platform_device *pdev)
return PTR_ERR(fsl_dev->regmap);
}
- id = of_match_node(fsl_dcu_of_match, pdev->dev.of_node);
- if (!id)
- return -ENODEV;
- fsl_dev->soc = id->data;
-
drm = drm_dev_alloc(driver, dev);
if (!drm)
return -ENOMEM;
diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h
b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h
index 2a724f3..7c296a0 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h
@@ -114,8 +114,6 @@
#define DCU_UPDATE_MODE_MODE BIT(31)
#define DCU_UPDATE_MODE_READREG BIT(30)
-#define DCU_DCFB_MAX 0x300
-
#define DCU_CTRLDESCLN(layer, reg) (0x200 + (reg - 1) * 4 + (layer) * 0x40)
#define DCU_LAYER_HEIGHT(x) ((x) << 16)
@@ -155,6 +153,9 @@
#define DCU_LAYER_POST_SKIP(x) ((x) << 16)
#define DCU_LAYER_PRE_SKIP(x) (x)
+#define VF610_DCU_MAX_REGISTER 0x11fc
+#define LS1021A_DCU_MAX_REGISTER 0x5fc
+
#define FSL_DCU_RGB565 4
#define FSL_DCU_RGB888 5
#define FSL_DCU_ARGB8888 6
@@ -175,6 +176,7 @@ struct fsl_dcu_soc_data {
unsigned int total_layer;
/*max layer number DCU supported*/
unsigned int max_layer;
+ unsigned int max_register;
};
struct fsl_dcu_drm_device {
--
2.7.0
